The number of lower limb paralyzed patients caused by stroke, spinal cord injury and traumatic brain injury is very large and shows an uptrend. After symptomatic treatment of acute stage, paraplegic patients often need longer-term rehabilitation to restore lower limb motor function. Therapeutic exercise is a common method for lower limb rehabilitation. The traditional rehabilitation method is that the patient's lower limbs are driven manually by therapist to do rehabilitation training. So, it is very subjective and time-consuming, and the effect is not satisfactory. As a kind of automated, accurate, intelligent medical equipment, rehabilitation robots have strong advantages in providing continuous, quantitative rehabilitation training, can effectively overcome the shortage of traditional rehabilitation methods and have broad application prospects. In clinical rehabilitation training, different postures and trajectories are often applied in different rehabilitation stages to get better recovery result. For patients in early rehabilitation stage, passive training of lying posture is often used to prevent muscle atrophy and to reduce complications. For patients in midterm rehabilitation stage, the training posture needs to translate from lying to standing to overcome the problem of orthostatic hypotension. During the later rehabilitation stage, patients usually have certain lower limb muscle strength, and hence, it is possible to consider passive or active gait training with the help of weight support system to overcome a part of body weight. It makes patients restore independent walking ability and back to activities of daily living as early as possible. At the same time, for the patients in the early and middle stage, bicycle training of the sitting posture is usually used in practice. This training method can be achieved by a relatively simple rehabilitation bicycle. The training cost is lower and the training preparation process is faster, and hence, the method can be applied to the high intensity and frequency rehabilitation training. Currently, rehabilitation bicycles are widely used in the rehabilitation therapy for patients with lower limb paralysis.
However, for most existing rehabilitation robot systems, the training trajectories are designed for a certain training posture. It is difficult to meet the paralyzed patient's training needs of different rehabilitation stages. Besides, it is difficult to design and optimize the rehabilitation prescription based on the same platform and standard to get the best recovery result.